       Re: Derivatives

• To: mathgroup at smc.vnet.net
• Subject: [mg113727] Re: Derivatives
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Tue, 9 Nov 2010 03:53:28 -0500 (EST)

```I think you're asking whether Mathematica can do implicit
differentiation.  The answer is yes.  Here's a rather simple example.

eq n= y x^4+4x^2 y+x^ 3== 8 ;
neweqn = eqn /. y - >y[x] ;
deriveqn = D[neweqn, x]
derivative = y'[x]/.First@Solve[deriveqn, y'[x]]
yvalue = y /. First@Solve[eqn, y]
derivative /. y[x] - >yvalue

On 11/8/2010 3:37 AM, will wrote:
> Hello,
>
> I am trying to take the derivative (d/dx) of a very messy equation
> that is more easily expressed initially as a function of y, then y and
> a function of x. Rather than have to substitute and expand, can a set
> of equations be input  and instructed to find a derivative wrt x?
>
> (A little bit new to Mathematica)
>
> Thanks.
> Will
>

--
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

```

• Prev by Date: Re: Infix doesn't worj with precedence and grouping
• Next by Date: Re: DownValues